Air pollution in China, especially in mega-metropolitan areas, is a matter of concern due to its impact on public health; outdoor PM2.5 exposure contributed to approximately 1.22 million deaths in China in 2013. China’s measures to improve its air quality are working, but more stringent policies should be put in place to safeguard public health, according to a new open-access study by researchers at Tsinghua University published in the journal Environmental Research Letters.

The study used satellite-derived aerosol optical depth measurements, ground based observations, and air quality simulations to evaluate the air quality and health benefits associated with China’s stringent policies implemented during 2013-2015.

The research confirms the effectiveness of China’s clean air actions, including promoting end-of-pipe control measures, limiting coal use in small combustion devices, retiring old vehicles, and many others. The results show that the action plan led to a 21.5% reduction of population-weighted mean PM2.5 concentration in just two years.

This study estimated that the premature mortality related to PM2.5 pollution reduced by 9.1% as the consequence of air quality improvement.

The Chinese government has made well-publicised moves to improve air quality and reduce pollution across the whole country, through its Air Pollution Prevention and Control Action Plan (the action plan). Our study marks the first estimates of the impact of this stringent action plan on pollution levels and mortality rates from 2013 to 2015.

The smaller health benefits compared to reduction in PM2.5 concentration is due to the non-linear relationship between pollution and mortality in current exposure-response functions. PM2.5 concentrations in polluted Chinese provinces are still at the high concentration end, where marginal mortality reductions are relatively small. Therefore, to improve air quality and achieve larger public health benefits in these regions, the government must continue to enforce clean air actions so that public health improves further, and more stringent actions are on the way.

It should be noted that the exposure-response functions used in this study is primarily developed by epidemiological studies in developed countries, and subject to uncertainties. More direct evidence from local studies could help us to improve the estimates.

—Lead author Yixuan Zheng

Senior author Professor Qiang Zhang said that it is most likely China will be able to achieve its action plan goals: reducing PM2.5 concentration by 25% in the BTH region during 2013-2017. However, continuous efforts should be placed in the future because PM2.5 concentration in BTH is still well above the standard.

Our study affirms the effectiveness of China’s recent air quality policy; however, due to the nonlinear responses of mortality to PM2.5 variations, current policies should remain in place and more stringent measures should be implemented to protect public health.